articleBone microarchitecture is receiving increasing attention in theassessment of the biomechanical properties of bone. While it iswell characterized in normal and pathologic human subjects,few quantitative data are available in human fetal development.In this paper, quantitative parameters of bone microarchitecturein developing human bone are reviewed from the literature andsupplemented by new data from the femoral metaphysis of hu-man fetuses. The samples were imaged using synchrotron radi-ation 3D micro-CT and processed using customized analysismethods. This technique provides 3D model independent mor-phometric parameters, anisotropy, connectivity and geometrycharacteristics, as well as information on mineralization.The morphometric parameters obtained on fetal vertebrae andfemurs evidenced a dense trabecular structure as comparedto that of young adults. The histomorphometric and the 3D mi-cro-CT analysis were consistent to show a significant in-crease of trabecular bone volume with gestational age. Tra-becular bone was found isotropic in vertebral bodies andanisotropic in femoral metaphysis, demonstrating a radialgrowth in vertebrae, and a longitudinal spreading out in longbones such as the femurs. Trabecular thickness in the maturebone of vertebral body and femoral metaphysis was around100 μm, which was in agreement with histomorphometric eval-uation. In the femoral metaphysis, three-dimensional analysisconfirmed the thickening of trabeculae with the distance tothe growth plate, and an estimated rate of thickening around 3μm/day previously obtained in histomorphometry. The 3D net-work was highly connected, and our new geometrical analysistechnique showed a strong prevalence of rod structure ascompared to the plate structure in cancellous bone